Which species will win or lose as Antarctica’s ice melts?

Scientists are closely watching Antarctica’s ice sheets as human-driven global warming melts the continent. But few studies have focused on what’s happening to ice-free areas — the places that penguins, seals, plants, and microbes call home.

Australian researchers this week took a closer look at the rocky outcrops, cliff faces, and mountaintops sprinkled throughout Antarctica. They found these isolated habitats will experience significant changes as ice shelves and glaciers melt due to warming air and water temperatures.

Permanent ice-free areas, which now cover about 1 percent of the continent, could grow by 6,600 square miles — a 25-percent increase — during this century, according to their study published this week in the journal Nature.

Image: Peter Ryan/Australian Antarctic Division

An ice-free area at Mt. Siple, Marie Byrd Land, West Antarctica. An Adélie penguin colony is visible in the foreground.

The report is the first quantitative assessment of how climate change will affect Antarctica’s ice-free areas in the 21st century.

Antarctic habitats, which today are separated by miles and miles of ice, will increasingly merge in coming decades, expanding areas for native species to grow but also creating new opportunities for invasive species to spread, researchers found.

While more competitive natives could survive and thrive, others may be driven to extinction.

Some Antarctic mosses, for example, could grow faster as temperatures rise. Antarctica’s two flowering plant species may continue their southerly expansion. But newcomers, such as the invasive annual meadowgrass Poa annua, could snuff out natives as they spread across newly ice-free areas.

Image: Lee et al. (2017) Nature

Projected Antarctic ice melt this century.

"Will this increase in habitat availability benefit the plants and animals that live there? It will definitely provide new opportunities for some native plants and animals to expand their range and colonize new areas," Jasmine Lee, the report’s lead author, wrote in a post on The Conversation with coauthors Justine Shaw and Richard Fuller.

"However, the potential benefits seem likely to be outweighed by the negatives," the scientists wrote. "The joining-up of habitat patches could allow species that have been isolated for much of their evolutionary past to meet suddenly."

This merging may eventually lead to the loss of many plant and animal species in the coming centuries and the "homogenization" of Antarctica’s ecosystems.

Image: Jasmine Lee/Australian Antarctic Division

An ice-free cliff in Marie Byrd Land, West Antarctica.

Lee and her coauthors said the study highlights the need for scientists and tourists alike to take extra precautions when visiting the continent. Bags, shoes, clothes, and field equipment can all carry non-native seeds, microbes, and insects if they’re not properly cleaned and inspected before arrival.

"We call for protection of ice-free areas that will remain intact in a changing climate, and for the Antarctic scientific and tourism communities to pinpoint key areas where greater biosecurity and monitoring for invasive species may be needed," the researchers said.